Thread[#143,ForkJoinPool-1-worker-1,5,CarrierThreads]
    java.base/java.lang.VirtualThread$VThreadContinuation.onPinned(VirtualThread.java:185)
    java.base/jdk.internal.vm.Continuation.onPinned0(Continuation.java:393)
    java.base/java.lang.VirtualThread.parkNanos(VirtualThread.java:631)
    java.base/java.lang.System$2.parkVirtualThread(System.java:2648)
    java.base/jdk.internal.misc.VirtualThreads.park(VirtualThreads.java:67)
    java.base/java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:267)
    java.base/java.util.concurrent.FutureTask.awaitDone(FutureTask.java:497)
    java.base/java.util.concurrent.FutureTask.get(FutureTask.java:203)
    io.sentry.HostnameCache.updateCache(HostnameCache.java:121)
    io.sentry.HostnameCache.<init>(HostnameCache.java:77)
    io.sentry.HostnameCache.<init>(HostnameCache.java:64)
    io.sentry.HostnameCache.<init>(HostnameCache.java:58)
    io.sentry.HostnameCache.getInstance(HostnameCache.java:52)
    io.sentry.MainEventProcessor.ensureHostnameCache(MainEventProcessor.java:192) <== monitors:1
    io.sentry.MainEventProcessor.setServerName(MainEventProcessor.java:181)
    io.sentry.MainEventProcessor.processNonCachedEvent(MainEventProcessor.java:132)
    io.sentry.MainEventProcessor.process(MainEventProcessor.java:146)
    io.sentry.SentryClient.processTransaction(SentryClient.java:416)
    io.sentry.SentryClient.captureTransaction(SentryClient.java:661)
    io.sentry.Hub.captureTransaction(Hub.java:700)
    io.sentry.SentryTracer.finish(SentryTracer.java:264)
    io.sentry.SentryTracer.finish(SentryTracer.java:565)
    io.sentry.SentryTracer.finish(SentryTracer.java:558)
    io.sentry.SentryTracer.finish(SentryTracer.java:553)
    io.sentry.spring.jakarta.tracing.SentryTracingFilter.doFilterWithTransaction(SentryTracingFilter.java:127)
    io.sentry.spring.jakarta.tracing.SentryTracingFilter.doFilterInternal(SentryTracingFilter.java:87)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
    org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174)
    org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149)
    org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
    org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174)
    org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149)
    io.sentry.spring.jakarta.SentrySpringFilter.doFilterInternal(SentrySpringFilter.java:71)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
    org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174)
    org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149)
    org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:167)
    org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90)
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:482)
    org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:115)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93)
    org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:344)
    org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:391)
    org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63)
    org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:896)
    org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1744)
    org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52)
    java.base/java.lang.VirtualThread.run(VirtualThread.java:311)

private void ensureHostnameCache() {
    if (hostnameCache == null) {
      synchronized (this) {
        if (hostnameCache == null) {
          hostnameCache = HostnameCache.getInstance();
        }
      }
    }
  }

    private final ReentrantLock lock = new ReentrantLock();

    private void ensureHostnameCache() {
        if (hostnameCache == null) {
            lock.lock();
            try {
                if (hostnameCache == null) {
                    hostnameCache = HostnameCache.getInstance();
                }
            } finally {
                lock.unlock();
            }
        }
    }